The invention provides a fastening structure capable of compensating tolerance. The fastening structure is simple, convenient to operate and capable of realizing quantitative adjustment among accessories and reducing assembly size errors. The fastening system is assembled between a mounting metal plate and a fastened workpiece, a mounting bolt is sequentially screwed into the fastened workpiece, the fastening system and the mounting metal plate and then is locked through a projection welding nut, the fastening system comprises a limiting piece, a mounting connecting piece and an adjusting piece, the limiting piece is assembled on the fastened workpiece in a limiting mode, the mounting connecting piece is assembled on the limiting piece, the adjusting piece is in threaded connection in the mounting connecting piece, and a first holding mechanism is arranged in the limiting piece, so that the limiting piece, the first holding mechanism and the mounting bolt can be held tightly; a second holding mechanism is arranged in the adjusting piece, so that the adjusting piece, the second holding mechanism and the mounting bolt can be held tightly; a first stop block is arranged on the outer wall of the mounting connecting piece; a limiting structure is arranged on the fastened workpiece, and the limiting structure is provided with the movement allowance of the first stop block on the plane where the fastened workpiece is located.